Fireproof quartz brick or block.



45 same quantity of lime.

ERNST STQFFLER, OF ZURICH, SWITZERLAND.

FIREPROOF QUARTZ BRICK OR BLOCK.

- Specification of Letters Patent.

Patented Nov. 21, 1905.

Application filed May 11, 1904. Serial No. 207,479.

To aZZ whom it may concern:

Be it known that I, ERNST SToFFLER, residing at 72 Forchstrasse, Zurich,Switzerland, have invented new and useful Improvements 5 in FireproofQuartz Bricks or Blocks; and I do hereby declare that the following is afull, clear, and exact description of the invention, which will enableothers skilled in the art to which it appertains to make and use thesame.

Experiments in connection with the manu facture of artificial stone fromsand or quartz and dolomite have shown that pure magnesia in certaincircumstances can serve as the I binding material in a similar manner tothat already made known in connection with the I employment of lime andsand. Furthermore, the use of magnesia in lieu of lime has the advantagethat when the magnesia mixture is slaked the magnesia possesses less inclination to form concretions than the lime mixture, which is ofconsiderable weight in the manufacture of homogeneous mixtures, sincefor the manufacture of good bricks or blocks it is essentialto'completely slake all the lime or magnesia particles.

Even although it could not be shown that magnesia bricks or blockspossess higher fireresisting properties than lime bricks or 3 blocks,yet with equal contents of lime or magnesia it has been proved that limeand sand bricks or blocks expand much more under heat than magnesia andsand bricks or blocks. Bricks containing seven per cent.

of lime or magnesia expand in the case of 4 wherein it is rather aquestion of a high degree of hardness or strength than of highfireresisting properties it has been shown that sand bricks made withmagnesia are more difficult to melt than bricks made with the Forexample, if the lime-sand brick melts at about Seger cone 10 (1,330centigrade) bricks made with the same quantity of magnesia in place ofthe lime show a melting-point at Seger cone 15, (1,430 centigrade.) Allexperiments indicate that bricks made with magnesia instead of limepossess properties differing considerably from those of lime-sandbricks. Furthermore, while on burning Dinas bricks made with an additionof lime and not steamhardened an active reaction is observed between thesilicic acid and the lime and a consequent considerable hardening,(rigidity) This does not take place to the same extent when magnesia isemployed as the binding material in the manufacture of such bricks.Experiments in burning artificial sand bricks containing magnesia as thebinding material in cases where the burning was not preceded bysteam-hardening did not result in the production of sufficiently strongbricks, probably because the binding material-namely, magnesiadid notcome fully into action. The action of the magnesia is, however, quitedifferent when the magnesiasand bricks before burning are hardened insteam vessels under steam-pressure. The hardness at tained on burning isthen sufficient, as is shown by the above-mentioned experiments.

After burning they are in many respects better than Dinas bricksmadewith lime. From the different qualities possessed by hardened andunhardened magnesia-sand bricks it would seem that the mixture ofmagnesia and quartz undergoes alteration on hardening understeam-pressure, this alteration securing the result that on burning,strong magnesia-sand bricks are obtained. All quartz materials do notshow equally favorable re sults with this method of treatment, thosematerials which expand considerably on burning being least suitable.From these materials, however, strong fireproof bricks can be obtainedwhen the quartz rock or sand is subjected to a heating process and thenchilled with cold water before being pul- Verized and molded. The uartzso baked produces with magnesia as the binding material a good fireproofbrick. While Dinas bricks made with lime show a considerable tendency tobend or warp at high temperatures, this tendency in the case of magnesiaand sand bricks manufactured in accordance with my process at hightemperatures, such as 16 Seger cone (1,450 centigrade) and 17 Segercone, (1,470 centigrade,) is so small that it can be looked upon forpractical purposes as non-existent.

Having now particularly described and as certained the nature of my saidinvention hardening them With steam and then burnand in whczlat 1mannlerthe saitne1 is to be pering the hardened bricks. formed, I ec are t atWiat c aim is The herein-described process of making ERNST STOFFLER'fireproof brick, which consists in mixing sand i Witnesses: or itsequivalent with magnesia alone as a ALBERTO BOLLIGER, binding material,molding the bricks, then i JOSEPH ABBoNnIo.

